In 2011, Japan experienced a nuclear disaster related to their power generation. This was at Fukushima. This incident led to the Japanese Cabinet giving a nod to a new energy policy aimed at turning Japanese buildings to zero-energy buildings. The policy looks to turn all newly-constructed buildings to zero-energy by 2020 while it hopes to turn all newly-constructed houses to zero-energy by 2030.

Before the Fukushima incident, 33% of Japan’s energy needs were generated and supplied by nuclear power. This changed in the wake of the incident, however, with all of the nuclear reactors in the country undergoing shutdown so that they can be inspected. The void left by the closure of these reactors has been filled by fossil fuels which are comparatively more expensive and has inevitably led to an increase I energy bills in the country.

With an increase in energy spending due to a steady increase in consumer energy consumption over the last three decades, it became necessary that an alternative means of generating energy are pursued.

It is for this reason that the energy policy to turn all new buildings to Zero Energy Houses (ZEH) was devised and approved. A Zero Energy House is a house that uses less net power than it creates on a yearly basis. In other words, a Zero Energy House produces its own energy which is more than the energy it utilizes. ZEHs produce renewable solar energy via photovoltaic cells which are installed on the roofs of houses. The energy produced via this means is then utilized in the day to day running of the building and the surplus sold to energy companies.

While the major way of generating energy for Zero Energy Houses is via renewable sources, there are instances where they utilize non-renewable sources of energy too although they usually compensate for this through the production of extra power at other times.

Photovoltaic cells used by these Zero Energy Houses are combined with Home Energy Management System (HEMS) to ensure an increase in energy efficiency. This combination constitutes what is known as smart houses which are houses where there is efficient consumption of energy.

The Japanese government has, through the introduction of subsidies, encouraged more construction companies and buildings to install HEMS devices. This has led to an increase in the number of smart houses in Japan as well as a target to have HEMS devices installed in every household by 2030.

HEMS devices help to reduce the consumption of energy. This is done through the monitoring of energy and gas usage in the building and subsequent manipulations to optimize consumption.

HEMS devices are seeing increased installations across the world especially in Europe. People the world over are recognizing the need as well as the benefits attributable to efficient and conscientious use of energy. And it is not farfetched to expect governments across Europe (and the world over) to start introducing measures of their own in order to encourage the springing up of smarter houses all over.