Microgeneration: using your electric vehicle as a power source

You might not realise it, but the batteries in your EV are amazing. As drivers, we focus on how far they can get us down the road but when we're not driving they're wired up to the mains. Believe it or not, they could play an important role in storing power and even providing it back to the National Grid.

For owners used to hooking up, charging up and driving off, it may seem like an odd idea but much of the time EVs are sat outside, charged and going nowhere. Even a modest 22kWh battery contains enough electricity to power a home for a couple of days, so if we're not planning on driving it could be a practical way to keep the lights on.

More than that, lots of EVs together can store enough power to make a major contribution to the National Grid. But why would they need to, when the grid brings abundant, relatively cheap electricity to our doors? Good question – let's find out.


What is microgeneration?

Microgeneration is the small scale production of electricity or heat by households, businesses or communities, as an alternative or to supplement what is acquired from the grid.


Why should I consider microgeneration?

Most often, microgeneration comes from renewable sources such as solar or wind, most of which are getting cheaper and more affordable to install and maintain. This is one of the key motivations for microgeneration; aspiring to a zero or low carbon footprint.

Producing your own energy isn't the only way to power your home or business from environmentally friendly sources though. Most energy suppliers now offer tariffs where the energy is guaranteed to come from renewable sources.

With energy prices increasing, microgeneration is also viewed as a way to lower overall power costs. Although a significant outlay for the equipment, free electricity is generated from renewable sources, which can cover the cost of the equipment in the long term and lower bill amounts. Income can also be or by generated by selling excess electricity back to the power grid.


How can I make money from microgeneration?

From January 1st 2020, all energy suppliers with at least 150,000 domestic customers will be required to buy excess renewable energy generated by its customers under the Smart Export Guarantee (SEG).

This scheme replaces the feed-in tariff scheme previously offered by the UK government up until the end of March 2019.

Suppliers are able to set their own rates for purchasing electricity, the only requirement is that the tariff must be greater than zero at all times. As such prices per kWh range from 3p to 6p.


Microgeneration technologies

Microgenerating electricity and heat most often comes from these renewable microgeneration technologies:


Solar Panels

Solar photovoltaic (PV) panels convert sunlight into electricity - they do not need direct sunlight to work, however the stronger the sunshine, the more electricity is produced. Solar panels are becoming increasingly cheaper and more efficient.


Wind Turbines

Wind turbines work as the wind rotates a propellor that in turn turns a motor to generate electricity. For microgeneration, wind turbines can be anything from 1 metre to 8 metres tall. The energy they produce depends on the wind they receive.


Hydro Turbines

Hydro turbines, like wind turbines, generate electricity by turning a motor. The source of the energy of course is flowing water, so great if you're next to a river or stream. Unlike solar and wind, hydro produces energy continuously.


Heat Pumps

A heat pump is a device that uses a small amount of electricity to move heat from one location to another through a cycle of evapouration and condensing using a refridgerant as a medium to release heat. A refrigerator is a common example of a heat pump on a reverse cycle.

Since the ground and air outside always contain some heat, a heat pump can supply heat to a house even on cold winter days. In fact, air at –18°C contains about 85 percent of the heat it contained at 21°C.



Biomass, or anaerobic digestion, is energy generated from burning organic plant and animal materials such as wood, food scraps, animal manures, fats, oils and more, in a container or 'digester'. As the organic matter is burned they release a biogas, which can be used to generate heat and power. While this may not sound environmentally friendly, burning these types of fuels only releases the carbon dioxide that was collected during their life time.


How can electric vehicles support microgeneration?

Until pretty recently, electricity came from a big power station that generated a steady supply into the grid. In recent years, however, more and more of the UK's energy mix has come from renewables – in the second quarter of 2018 it reached a record 31.7%. Renewables are an ongoing success story in reducing CO2 emissions worldwide, but managing and distributing them can be a challenge.

The problem is the unpredicatble nature of weather. On windy, sunny days there can be more energy generated than we can use. So what happens to that energy? We lose a lot of it. This is where electric vehicles can help with their biggest asset, their batteries.

Imagine that one in 100 of the UK's 27 million households own a Nissan leaf. Some 270,000 cars, each with a 40kWh battery could store an incredible 10.8GWh of power to release as needed when renewable generation is lower - that's more than the UK's biggest storage facility, the Dinorwig pumped storage plant in Snowdonia.


What is the smart grid?

Imagine an internet for gas and electricity – a smarter way to run our national energy networks in the 21st century. That’s the smart grid.

As technology evolves, the idea of households storing energy in their cars or domestic batteries could become a key part of a new, smarter National Grid. If everyone can store electricity, power companies can finally separate supply from demand. They could produce electricity when it's cheapest and most efficient, or when renewable sources like sunlight or wind are most abundant, and consumers can store the power at home, ready to use or to supply back to the grid at times of peak demand.

Microgeneration in homes reduces the amount of electricity that power companies need to produce, but if the excess power is stored it's also available to help the grid meet peak demand.

It probably sounds futuristic, but homeowners have long been paid to sell power back to the grid through the feed-in tariff scheme. Now power companies are trialling vehicle-to-grid charging specifically to exploit the increasing popularity and capacity of electric cars. In the near future, your EV could be helping smooth out the peaks and troughs of renewable energy, and potentially helping the UK phase out more of its high-carbon conventional power stations.

In itself, that's pretty satisfying, but vehicle-to-grid also gives EV owners the reassurance of a backup power supply for their home. The icing on the cake is that power companies will pay for the energy they buy back – a great way to get a return from your investment in an EV and to make electric motoring even cheaper.


Microgeneration Certification Scheme (MCS)

The microgeneration certification scheme, often recognised at the MCS certificate, is a quality assurance scheme supported by the Department for Business, Energy & Industrial Strategy (BEIS) and designed to ensure microgeneration products and installation companies meet high standards.

It's a requirement of the domestic Renewable Heat Incentive scheme that all heating systems are certified by MCS, and you'll need to provide an MCS certificate number with your application to confirm the system has been installed in line with the MCS installation standards.

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