What do Large Solar Power Plants mean for Solar Roofs? 

Industrial Unit Solar Panels

The secretary of state will be reviewing a proposal for the largest solar plant ever built within the next 6 months. If building goes ahead the Cleve Hill solar farm will occupy the north coast of Kent and provide up to 350 megawatts of generating capacity, five times the capacity of the UK’s current largest solar farm. Although there have been subsidy free solar installations before, Cleve Hill will be the biggest one yet covering 1,000 acres of land. It is planned for Cleve Hill to generate the lowest cost electricity on the UK network. Operators will have the option of storing energy when the electricity price is low and selling when it’s high as the plant will also include battery storage. From a grid control point of view, a 350MW solar farm with a battery store is the perfect answer for network operators as the power flows can be monitored making it easy to make predictions because any additional generation will be stored onsite. 

 Max Wakefield said recently in the Guardian: 

 “It’s a real ray of sunshine to see such ambitious clean energy projects emerging in the UK despite the policy obstacles.” 

This is very much a turning point for the UK’s electricity supply. The UK has nearly a million solar panels including solar panels mounted on roofs and farms occupying entire fields.  

Up until now the government has overseen the growth of solar power by controlling the level of subsidy they were willing to offer. When the subsidies were high the installation rate grew hugely, when they fell installation rates dropped to a very low level.  

Cleve Hill could change all that by showing that it is possible to make money without there being any subsidies. As solar power generation becomes much cheaper and the government becomes less able to control solar power growth using subsidies and incentives it is possible that solar panels on roofs will make more financial sense. Will we start to see a balance of large and small systems being installed without subsidy?  

There is no doubt that the Cleve Hill solar plant would indicate the moment when solar power becomes self-reliant. Cleve Hill definitely makes financial sense because it’s so big though this and other similar plants would have an environmental impact.  

The public can see the sense in solar panels on roofs because electricity generation is happening at the point of use. Solar farms make sense to investors because they are cheaper to install per unit of electricity but also bigger – so finance can be accessed in larger chunks and investors can make more money.   

However, Cleve Hill has to get agreement at the highest level of government and has to be developed with input from local authorities and electricity network operators to become part of the national infrastructure. Subsidy free rooftop solar would be far less controlled. Will this present a big problem or a golden solution?   

This year the UK has had an unusually sunny summer. On Saturday 30th June at Midday solar produced 30% of the national demand for electricity. There were days during this period when a combination of wind and solar power provided 50% of UK energy. If you include nuclear power, there were several occasions this year when the demand for energy from gas and fossil fuels fell to about 20% of the UK’s requirements.  

If subsidy free solar power was to be a real possibility, solar installations could double in number over the next few years and reach a 25-gigawatt peak capacity. If these were new rooftop systems deep within the electricity network where there is high demand it would still be problematic to balance supply and demand as rooftop solar is difficult to track and measure.  

Perhaps there will be more subsidy free solar farms to begin with but as costs drop and the number of sensible sites for solar farms become less, rooftop solar power will become a better economic proposition again.  

What is becoming clearer is that if Cleve Hill can make money without subsidy then we can almost certainly expect a low carbon future which includes a large solar power contribution.  

Find out more about solar here. 

How is Climate Change Impacting the UK?


Since the 1970s temperatures in the UK have risen by approximately one degree. With the level of greenhouse gas already in the atmosphere it follows that there will be further warming in the next three decades. The UK will have to adapt to the impact of climate change even if emissions are cut quickly and sharply to avoid the levels rising to a dangerous extent.

Greenhouse gases trap some of the sun’s rays causing the planet to heat up. Continuing to burn fossil fuels like coal, oil and gas increases these gases in the atmosphere.

The UK has made it a rule of law to reduce its emissions by at least 80% below 1990 levels by 2050. To this end the Committee on Climate Change has set carbon budgets up to 2032.  Overall the UK’s greenhouse emissions were 42% below 1990 levels in 2016. However, the CCC has warned time and again that we are off track for the 4th carbon budget as climate policy has been weakened in very recent years in the areas of energy saving and renewable energy.

One of the key climate threats for the UK is the risk of flooding alongside stresses on water resources, threats to biodiversity and natural habitats.

Studies have been done that show that extremely wet winters could become up to five times more likely over the next century with more intense downpours in the winter months driving a greater risk of flash floods and river flooding alongside risks from sea level rise.

Nicholas Stern said recently in the Guardian:

“We must reduce greenhouse gas emissions to net zero or face more floods.”

Conversely, studies suggest that the UK could experience warmer, drier summers in the future leading to an increased risk of drought. Heatwaves could become the norm by the end of this century. Extreme heat can have a detrimental effect on the more vulnerable older population, create travel delays with the buckling of railways, threaten water supplies and security and destroy valuable ecosystems.

The Paris Agreement commits nations to pursue efforts to limit warming to 1.5°C.  As it stands current UK targets give us at best a 50% chance of hitting 2°C.  Many scientists think this is way too risky.

In order to attain the level of warming agreed the UK needs to shift to a renewable energy grid. Renewable sources of energy from wind, wave and sun need to account for 75% of our electricity by 2030.

The UK has had success with renewables as demonstrated in 2016 when renewables were responsible for providing 25% of UK electricity. This was up from just 7% in 2010. Government lent it’s support for renewable power in the early 2010s and took action to make coal power pay for its pollution costs. From May to September in 2016, solar power produced more electricity in the UK than coal.

Onshore wind is now the cheapest form of new electricity generation. It is now cheaper than new gas power stations.

With these trends and the major advances in energy storage, renewable energy is set to become the dominant player at the heart of a clean UK energy system within the next decade.

Find out more about solar here.

Is it Time to Take Power Back from the Energy Companies?

National Power

In recent years more, people than ever are considering moving ‘off grid’. Grids are centralised systems that distribute energy in the form of electricity and gas to where it is needed. Supply and demand are carefully matched with the grids often buying excess renewable energy from consumers to keep the grid fully fed during energy lulls.

Disconnecting from this grid means leaving the safety net that it provides. In the past this would have meant seriously limiting energy use when the sun wasn’t shining, or the wind wasn’t blowing. Now however with the advances made in storage technology it is possible to store excess renewable energy for these times instead of selling the extra energy back to the grid. However, the question of whether we can produce enough energy remains. In the UK where an average family uses around 125 kilowatt hours per day, keeping your home heated consumes a lot of energy.

The answer to being able to produce enough energy to live off-grid is to use a range of solutions. The simplest option for keeping warm is to burn biomass (wood and other organic material). Natural heat can be extracted from our surroundings using solar thermal collectors and ground source heat pumps to heat water systems. Though expensive to buy they are efficient and so a good long-term investment, paying for themselves in a matter of a few years.

Being able to satisfy all the electricity demands of modern lifestyles presents more of a problem. The most popular choice is currently to use solar energy systems. Your power supply can be supplemented with a leisure battery. It’s best to invest in a deep cycle battery that can handle being run down and charged up again more frequently than a car battery.

Using wind power makes less sense for the individual household.  A roof mounted turbine provides less than a quarter of the roughly 45,000 kilowatt hours that households in the UK use in a year. Purchasing a full-size 6kW turbine if you have got enough space will cost at least £20,000 and might take the whole lifespan of the turbine to cover the costs.

Hydro power is another alternative. Living near a stream or river may give you the option of producing micro-hydro electricity. Using the water’s current and a nifty bit of kit electricity can be generated all the time.

The question for most of us is whether going ‘off grid’ completely is affordable. The best solution if the costs of going ‘off grid’ are prohibitive is a partial move away from being totally dependent on the grid. Using solar PV technology makes the most sense and supplementing this with energy from burning wood.

One way of being less grid dependent is to use less energy and there are several good habits to get into to make ‘off grid’ living more viable.

  1. Switch to LED lights – they are 90% more efficient than incandescent bulbs. Turn lights off when not being used. Lighting accounts for around 15% of household electricity.
  2. Use cold water to wash your clothes as most washing powders are now designed to work at low temperatures. Dry clothes naturally whenever you can which also reduces the need for energy intensive ironing.
  3. Turn down the heat. One of the most intensive uses of energy in homes is heating water. Turning down the heating by a degree can reduce your heating bill by 10%.
  4. Insulate your home. Fit loft insulation to prevent up to a quarter of the heat in your home escaping and deal with draughts.
  5. Insulate yourself. Today we are likely to heat our homes more than four degrees warmer than we did 50 years ago. Put on another layer of clothing instead.

Should you Install a Tesla Powerwall or other Solar Battery?

Tesla Battery

People often want to know how they can improve their use of free solar power to reduce their electricity bills.

The Tesla Powerwall 2 has the capacity to store 13.5kwh compared to other systems that offer only 4-6kwh of useable storage. Using this cost-effective solar battery can help households make the most of renewable energy.

In a nutshell, the Tesla Powerwall is a rechargeable lithium ion battery with liquid thermal control as described by Tesla. Tesla is one of the few companies offering residential energy storage solutions. These battery packs are ideal to work in conjunction with solar panel systems and especially good for those homeowners who need or want to become independent of their utility.

As well as storing free solar energy during the day for release in the evening/night time the Tesla battery can be charged overnight for only a small charge per kwh from many companies.

When more electricity is produced by a household’s solar panels than can be used by that household the excess is stored in the battery pack instead of being sent back into the electric grid. This means that later in the day when a household’s solar panels aren’t producing enough electricity the electricity stored in the household’s Powerwall can be used rather than having to buy electricity from the utility.

The pricing of the smaller capacity systems ranges between £5,500 and £8,800 whereas Tesla can provide twice the capacity for £7,650.

If you take into account that self-builders installing new PV & solar batteries benefit from the zero-rated VAT this further reduces the pricing of the Tesla Powerwall 2 to £6,340.

However, if a household is looking to install the Powerwall as part of a solar plus storage system the battery costs are only one part of the equation. Several different factors need to be considered before installing this system into a home. Whether or not the Tesla battery pack is going to be worthwhile for a household depends on the way their electric utility structures its rates as well as their reasons for installing a solar battery.

It is important then to look at each household’s mains electricity usage, existing solar generation and pattern of consumption to work out how to make the best use of a Tesla battery.

Though installing a solar plus storage system is a great way for a household to take control of their electricity bill it doesn’t mean that the household is entirely disconnected from their utility. It is actually a more expensive and complex proposition to go ‘off the grid’ with solar batteries. One Tesla battery will only provide a few hours of backup power and is not nearly enough to cover a household if there is a full day of cloud or weeks of inclement weather.

Solar batteries are still a fairly new technology for homeowners. Though the benefits for some can be significant it isn’t always a necessary investment. Some utilities offer net metering which means that a solar battery won’t save you any money. If, however the homeowner is in an area with time-of-use electricity rates, no net metering or considerable demand charges then a solar battery would be a good choice for them.