My eco-home: going DC off-grid (nearly)

I have spent the last ten years of my career in the renewable energy and wider energy technology area. I have managed a renewable fund. I have advised global investors on where to invest their money and today I am advising companies on strategy, fund raising and M&A in the energy area.
I am convinced that our energy world is radically changing thanks to technologies such as solar, horizontal drilling, demand response, LEDs, batteries as well as exciting new business models from companies such as SolarCity in the power market or Tesla in the electric car area. And we have already seen, particularly in Europe, a huge build out of renewables which has forever changed our power markets.
And there’s me buying a house on the German-Polish border surrounded by trees, fields and water. A beautiful and tranquil place in the flood plains of the river Oder and I am surrounded by renewable energy, nature and eco-farmers.
We have a biogas power station outside the village. Most farmers have solar on their roofs. Most people use wood for heating purposes, and there are a large amount of wind turbines in the area. And a ten minute drive and I am at Neuhardenberg which is home to Germany’s biggest solar PV plant (145MW).
The house itself needs to be renovated and I have followed on from Denmark by banning the use of fossil fuels for heating systems.
That narrows my choices down to using biomass such as wood or geothermal/solar heat pumps or full electricity for heating and hot water. I looked at putting in a small CHP unit. I looked at wood pellets. I even looked at fuel cells. In the end I have decided to go fully renewable.
I will use solar thermal and a heat pump for my hot water and I will also put 10kW of PV solar on my roof. My goal is to buy as little power as possible from the grid and I am going to put intelligence and storage around it so that I use as much of that power as possible.
Storage will come in three forms, hot water in a tank, an electric car and if needed an extra battery system. I am also going to flexibilise the demand side to meet that solar production. I am also going to buy a BMW i3 (assuming BMW can actually organise charging stations in both Berlin airports) and again to charge it during the day.
I want an intelligent system that works automatically without my intervention but that I can also control with my mobile phone. And any electricity I do buy from the grid will be renewable.
I am also going to put in highly efficient devices in the home. The lighting will be LEDs and we will also put an infrared electric heating system which produces radiant heat just like the sun. And my wife is happy because she says that it produces a healthy and comfortable heat.
They also look good. They can be hidden behind pictures or as what we are going to do in the kitchen they can be made to look like black boards. I will also put in a wood fired heating range which will provide direct heat for the living room as well as heat for hot water.
Probably the most radical thing I am going to do is to wire the house for direct current (DC) purposes. It just makes no sense to me that we generated DC with solar panels, convert that energy to alternating current (AC)  and then convert them back to DC so we can power the whole range of digital devices that make up our modern lives.
And the power losses are up  to 20% as a result. I am also fed up having all those black transformer boxes around my house. What I want is to plug everything in as one does a mobile phone into a computer. A simple USB port for everything. I would go fully DC but the issue is that there are still a whole range of devices such as washing machines that need AC. But I know they are coming and I will be ready!
Source: Energy and Carbon. Reproduced with permission.


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