As our SME Landlord Survey (pdf) Opens in a new window revealed, a lot of work is needed to bring the UK’s housing stock up to increasingly demanding energy efficiency standards. With an ever-increasing focus on what we can do to make our buildings greener and more energy efficient, here we take a look at some new green technologies that could one day be the norm in the race to reach our net-zero targets.
Transparent solar energy
The sun has long been our friend when it comes to renewable energy, and solar panels are becoming an increasingly efficient way of generating low to zero-cost electricity or warm water. Could the next step be transparent solar panels? This technology harnesses light through windows and glass surfaces turning it into energy. Whilst tentatively in use in larger upgrades (see the technology in action cladding the Copenhagen International School Opens in a new window), there’s still some way to go however, as scientists work to make scaling-up the solution more efficient and viable for our homes.
Hydrogen for heat
Heat pumps, whether air source or ground, are fairly well known as an alternative to gas boilers (ask our neighbours in Norway and Sweden who have used these for years), but could hydrogen also be part of the solution here in the UK, to make heating more efficient and less harmful to the planet? With approximately 20m gas boilers in UK homes, replacing them all with heat pumps would be a massive undertaking and currently impossible for some buildings. Hydrogen technology uses the pipes already delivering natural gas to boilers, but replacing it with hydrogen. Using the infrastructure we already have may seem an easy fix, but there’s an ongoing debate about how green the solution is, as producing hydrogen at the scale required for nationwide home heating would almost certainly result in new carbon emissions to then be dealt with. Our head of sustainability Richard Winder predicts that hydrogen produced via wind turbines will be scaled up as far as economically viable to meet demand from the steel, chemical and certain other carbon-intensive sectors that can’t be met electrically. He suggests that any surplus may be stored and used to boost grid electricity when the sun isn’t shining and the wind isn’t blowing, though communities close to coastal hydrogen hubs may eventually be heated this way.
That said, the eventual solution to dealing with the UK’s boiler estate may be a mix of more traditional heat pumps and hydrogen; the results of pilot schemes in the UK using hydrogen in homes will inform the government’s decision on that in the coming years.
Hempcrete
A relatively new alternative to insulation and concrete hempcrete or hemplime is made with the woody pulp of hemp, mixed with lime and water. It’s durable, airtight, resistant to mould and pests, toxin-free and does a better job at storing heat than concrete and masonry. It can be used to form walls and to insulate the roof of new-builds, and for upgrading insulation in existing buildings; due to the way it sets hempcrete is ideal for insulating more traditional or historic buildings with tricky layouts. The use of lime in its production does have a carbon cost due to the heat used as part of the process, however as hemp absorbs carbon as it grows it more than cancels that out, making it carbon negative. The production of hemp is very quick, taking only four to five months to grow and harvest. Although hempcrete is unlikely to replace concrete as it’s unsuitable for standing water meaning it can’t be used for foundations, it could still become a mainstream building product.
Micro hydro generation
Working on the principle that moving water can generate energy, micro hydro generation installations divert water flow from a river, stream or waterfall, to a turbine to produce electricity, before returning the water to the source. Whilst micro hydro may not be seen on suburban estates any time soon, it could come into its own if a large property such as a farm has a water source running through it. For more rural areas where fast flowing water is a feature, community micro hydro installations could be an option to provide renewable energy to the surrounding homes.
Mechanical ventilation and heat recovery
These units – and the network of ducts that feeds into them - work by extracting polluted or stale air from the property, pass it over a heat exchanger to retain the heat from that air, then feed-back that recovered heat into the home’s air flow. It’s sustainable energy technology that can work with other renewable heating systems. Its perfect partner is a heat pump which also uses heat exchangers to multiply natural warmth in the air, ground or water outside into space heating and hot water - when the two technologies work together they’re even more energy efficient. Trickier to retrofit into homes than installing into new-builds, they could mean an end to radiators or underfloor heating, they would however also mean the end of cosy winter nights in front of the fire, since the system can’t work with open fires or wood burners.