Ground Source Heat Pump

ground source heat pump

Ground Source Heat Pumps – Their Cost, Their Installation and Their Efficiency

Heating accounts for a significant portion of a household’s energy demand and a ground source heat pump system can provide a cost-effective and sustainable way to warm a home. The pump uses a small amount of electricity to transfer naturally occurring heat from the adjacent ground into the house.  As the temperature just a couple of metres below the surface remains more or less constant at 11°C to 12°C, it is possible to design a very efficient heat transfer system.

How does it work?

A sealed loop of fluid-filled pipe is buried in the garden or driveway. The length required depends on the size of the home and the amount of heat required. An average system for a family dwelling will typically require pipework up to 100m long.  Vertically drilled boreholes and deeper pipes can be used in more confined spaces. Once installed, the ground is restored to its original condition and the system becomes invisible.

The ground source heat pump circulates water and antifreeze around this loop. The fluid absorbs heat from the ground before it passes through a heat exchanger.  Energy is then transferred to the heating and hot water circuits of the home. The cooled fluid flows back into the ground loop in a continuous process for as long as the heating is required. Some systems can also be designed to meet cooling needs in summer.

While there are some minor residual energy and carbon costs, hooking the pump up to a home renewable technology such as a solar panel can increase its sustainability credentials even further.

What properties are suitable?

Ground source heat pump systems are not suited to every type of property. In general, they work most efficiently in well insulated homes with a relatively even and low heat demand. They produce heat at a lower temperature than more conventional central heating so a larger area is required for heat distribution. Underfloor heating is the ideal partner, though large heat pump system radiators are available. The system also requires sufficient outside space for installation. While minimal on-going maintenance is required, there can be considerable disruption during installation, and the system tends to be more attractive for new-build or as part of a wider home improvement project.

A typical domestic ground source pump is the size of a large upright fridge freezer. To save indoor space they can be installed in an outbuilding or basement.  They just need to be as close as possible to the end of the ground loop pipe. With a typical noise level of a little over 40dB at one metre away, they are as quiet as a fridge.  That’s considerably quieter than a typical gas or oil central heating boiler.

What do they cost and how much will I save?

Costs and savings will be dependant on the size of the pump, the length and depth of loop installation, the energy efficiency of the property, the sort of heating system that is being replaced and whether any additional work is required on the wider home heating system.  A typical domestic installation costs £12,000 to £15,000, with annual running costs of £600 to £700. At current prices, the payback from a ground source heat pumps is unlikely to represent an attractive alternative to an established mains gas central heating system. However, installers claim energy savings of nearly £1,500 annually for a typical four-bedroom house when compared with standard electric heating, or around £600 when compared to oil-fired central heating. That represents a saving of nearly 5,000kg of CO2 emissions each year.  Government Renewable Heat Incentive grants are currently available for installation.

Their installation will also greatly improve your energy efficiency score on your EPC.

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Renewable Energy Keeps Getting More Popular

If you’d like to book an EPC for your home, simply contact us by phone or email, or fill in our contact form.

 

Renewable Energy Keeps Getting More Popular

renewable energy

Renewables enjoy a rising wave of support

The UK Government monitors public attitude towards renewable energy technologies and climate change through a regular survey. The tracker was launched in March 2012 by the Department of Energy and Climate Change (DECC), now part of the Department for Business, Energy and Industrial Strategy (BEIS).

Known as the ‘Energy and Climate Change Public Attitudes Tracker’ (PAT), the main survey is carried out annually in March, with three supplementary short surveys in June, September and December. The repeat questions track the public’s views on important energy issues.  Each survey is known as a ‘Wave’ and the results of the Wave 25 survey were published recently. Wave 25 comprised 2,102 face-to-face, at-home interviews with a representative sample of UK adults. The background and detailed data are available on the UK Government website (here).

The latest survey results suggest a rising tide of public anxiety over climate change issues, with 74% of respondents saying that they were ‘very concerned’ or ‘fairly concerned’. The rise from 71% in May 2017 is a continuation of a growing trend. Perhaps due to on-going coverage in the media, a greater proportion of the public now accepts that climate change is the result of human activity rather than natural process. Just less than 50% said that they believed climate change problems were caused mainly by human activity, compared to only 10% who believed they were down solely to natural processes.

The latest Wave 25 results show overwhelming backing for renewable energy technologies, especially solar power and offshore wind farms. A comparison with the results from previous years reveals that public support for the use of renewable technologies to supply electricity, fuel, and heat has been climbing steadily.  It has now reached 85%, the highest recorded level since the tracker was set up. Only 3% were opposed.

In terms of the individual clean energy technologies, solar was given the greatest vote of confidence at 87%, with offshore wind reaching a record high of 83%. Close behind came wave and tidal power at 81%, onshore wind turbines at 76% and biomass power stations at 69%. The survey results also seem to indicate a reducing NIMBY effect, with people getting used to seeing and accepting large scale renewable projects in their own areas. 66% now say that they would be happy to have a development locally, compared to 58% in the same month of 2017.

By comparison, support for nuclear energy was largely unchanged over the year at 38%, with 22% opposed. The public’s attitude to shale gas extraction also remained essentially stable at just 18% in favour and 32% opposed.

The Wave 25 survey also included questions about perceptions of home energy efficiency.  Interviewees were asked what two things they thought use the most energy in the home. The answers included central heating (71%), large appliances (45%), and hot water (37%). When asked about home energy efficiency measures, 78% had installed double glazing, 65% loft insulation and 44% cavity wall insulation. Awareness of under floor insulation and solid wall insulation was much lower than for the other energy efficiency measures.

A question was also asked about home Energy Performance Certificates (EPCs).  63% were aware of EPCs, an increase over recent years, but only 9% claimed to know the rating of their own home.

It seems renewable energy is here to stay and will continue to play a greater role in all of our lives.

If you’d like to book an EPC, please feel free to contact us.

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Energy Storage – What’s in Store for Out Electricity Supply

Energy Storage

What exactly is in store for our electricity supply?

Despite the drive to make our homes more energy efficient, the demand for electricity remains strong.  As the traditional generating stations come to the end of their lives and we strive for a lower carbon economy, there is an ever-increasing reliance on renewable sources of power. The costs are coming down, but wind is unpredictable and intermittent and we cannot rely on the sun to provide us with the electricity we demand at the flick of a switch, especially at night.

It looks as though energy storage will need to become an essential part of our electricity supply system if we are to achieve our green goals and keep the lights on. Electricity storage technology can overcome the issues associated with the intermittency of renewables and help to meet the morning and the evening peaks in demand, whether at a domestic, community or national scale.

At present, energy storage capacity in the UK represents a tiny part of our electricity consumption and depends heavily on a few pumped storage hydroelectric facilities. We are otherwise reliant on switching generating stations on and off, or on importing renewable hydropower from Norway to deal with the fluctuations.

Research into battery technology has really taken off. The Government’s January 2017 Industrial Strategy Green Paper (here) states:

Given the UK’s underlying strengths in science and energy technology, we want to be a global leader in battery technology…’

The Government went on to launch a £9 million competition to find ways of reducing the cost of energy storage technologies, including the Faraday Challenge – a £246m commitment up to 2021 on battery development for transport, home and industrial applications.

The costs of storage are reducing as this research progresses.  In its 2016 report to the Renewable Energy Association, The development of decentralised energy and storage systems in the UK, KPMG predicts that there will be a ‘steady cost decline of 12% per annum through to 2020…’ (available here).

At the moment, most of the interest is in lithium-ion batteries and this technology accounted for 83% of installed global storage capacity in 2016 (excluding pumped hydro). The costs continue to fall with close to a 20% reduction in 2016.  Some issues remain with the relatively short life of the batteries and a deterioration in their efficiency as they are cycled through charging and discharging.  The focus could change in the medium term to developments in hydrogen and heat storage that are creating some excitement.

Products are already appearing for domestic use. They are arguably led by Tesla which is building a ‘Gigafactory’ in the US to produce batteries for its vehicles and for other domestic and commercial uses. Once complete, Tesla expects the Gigafactory to be the biggest building in the world, and it will be entirely powered by renewable energy sources. The factory brings an economy of scale that should make batteries more efficient and affordable.

Tesla is already marketing its solar roof tiles and ‘Powerwall’ domestic energy storage systems. These harvest and store electricity produced during the day for use when household demand is greater in the morning, evening and at night.

New Records for Renewable Energy

Renewable Energy

Recently released figures show that 2017 was a great year for energy sustainability in the UK, with record-breaking levels of renewable energy production and historically low prices for electricity generated by the wind. It was our greenest summer ever, with nearly 52% of electricity generation between 21 June and 22 September 2017 coming from low-carbon sources.

For the first time in history, on 7 June 2017, low-carbon technologies (nuclear and renewables) provided more electricity than all of the fossil fuel sources combined (oil, gas and coal).

Another symbolic milestone was achieved on Friday 21 May 2017, the first full day since the Industrial Revolution of the 1880s when no coal was used to generate our electricity, an important step towards the Government’s commitment to phase out Britain’s coal power plants by 2025.

In the offshore wind industry, spectacular progress in turbine efficiency, larger turbine rotor sizes and growing experience with offshore engineering and maintenance technologies have all contributed to huge savings. Government figures show that the price paid for electricity generated by offshore wind farms fell by more than 50% in less than five years. The data suggest that new offshore wind farms that are due to open in 2022/23 will be viable with public subsidies as low as £57.50/MWh, compared with the £92.50/MWh subsidy that was secured for the Hinkley Point C new nuclear power station.

The UK now has the fourth greenest power system in Europe (and seventh in the world), and the British electricity sector has halved its carbon emissions since 2012, a remarkable record. Despite this, the UK is lagging behind schedule for achieving its longer-term carbon reduction targets. Going forward, other sectors will need to match the level of achievement of the electricity sector, and attention is being increasingly focused on transport and agriculture.

There is similar good news from the energy markets around the world. Global renewable energy capacity grew by a record amount in 2016, and nearly 25% of electricity came from renewable sources. Hydropower provided most of this, with contributions from wind and solar at around 4% and 1.5% respectively. 

Solar power is following in the footsteps of offshore wind as an increasingly viable technology, and power supply deals in countries around the world, including Mexico, Denmark, Egypt, India and the UAE, saw renewable energy projects being priced well below fossil fuel and nuclear power alternatives. 

Worldwide, new renewable energy projects accounted for some 161GW of new capacity in 2016 (a 10% increase over 2015 and another new record) at a cost of $242bn, which, despite representing a 23% reduction in investment compared to 2015, was greater than that for fossil fuel generation.  New solar power accounted for half of the new capacity, while wind power added a third and hydropower 15%.

Rooftop Photovoltaics – Solar PV

Solar PV

One of the most satisfying ways of improving your home’s energy efficiency is to take control of generating your own electricity. Solar PV (photovoltaic) panels are one of the renewable energy technologies that you can fit to your home to do this.

Renewables are powered by unlimited and naturally replenished resources like the wind and the sun. They produce less greenhouse gases than traditional generating technologies, with an average domestic solar PV system saving up to 2 tonnes of carbon dioxide emissions annually.

Solar PV panels convert sunlight into electricity. They are most efficient in summer sunshine, but will generate some electricity in cloudier conditions, and throughout the winter. The electricity replaces energy that you would otherwise buy from your supplier. When demand exceeds generation, your normal supply kicks back in to make up the difference.

Is my house suitable?

Solar PV panels are generally suitable for any house with an un-shaded roof area of at least 15m² that faces between south-east and south-west. They are more effective in the south of the British Isles than the north.

Are they easy to fit?

Most domestic systems comprise panels that sit on top of the existing roof, but solar tiles that replace the existing roof can also be fitted, but are approximately twice the cost. The new Tesla solar roof costs even more, but is available in a wide variety of slate and tile finishes, and comes with integrated battery storage.

Solar PV systems are quick and easy to install. The solar panels themselves require little to no maintenance, though an inverter may need replacing after about 10 years.

Will it save me money?

The installation cost for a typical solar PV system is £5,000 to £10,000. While this is a sizeable outlay, you will benefit financially in three ways.

Firstly, it will cut your electricity bill. An average domestic system generates approximately 3,800 kilowatt hours a year in the south of England and 3,200 kilowatt hours in central Scotland. That is free electricity you will not have to pay for.

Secondly, small solar PV systems are currently eligible for the Government’s ‘Feed-in Tariff’ (FiT). Your energy supplier pays you for the electricity that you generate, even if you use it yourself. The tariff levels are index-linked and guaranteed for up to 20 years.

Finally, you will receive a further payment from your energy supplier for surplus electricity that you sell back to the grid.

There are online calculators that work out specific costs and savings, but as a rule of thumb, domestic scale solar PV systems pay for themselves after 10 to 12 years, assuming they are benefitting from the FiT. The rules for the FiT change regularly and it has a ‘first-come, first-served’ annual budget limit, so check with the Government website (BEIS) before making a decision.

Applicants for the FiT must provide an Energy Performance Certificate (EPC) with their paperwork. An EPC rating of band D or greater is needed for the higher rate tariff.