Smart City

Smart Energy is a mixture of energy, consisting of “onsite energy” and “autonomous energy,” which are generated on the user side and “energy-savings” by users, together with commercial power from power companies.
Onsite energy is renewable energy, such as generation from solar, wind, and biomass, and the use of geothermal heat. Autonomous energy is co-generation using city gas etc. Energy savings can be described as passive design, which makes maximum use of nature, in forms such as light, wind, rain, heat, soil, and greenery. Smart Energy is a framework for a new age of energy, to make optimal and efficient use of these energy types throughout urban areas.
CEMS (Community Energy Management System) was introduced for energy and CO2 saving, as it predicts supply and demand on the supplier and the customer, practices demand control, and optimizes energy supply and demand for the whole urban area. Huge power outage due to natural disasters such as earthquakes and typhoons are becoming more threatening to people, and they are expecting Smart Energy to provide functions which would allow them to maintain a minimum level of daily life and work even when the power supply is out.

Smart grids are an important theme in smart energy. Large scale buildings are individually equipped with devices such as generators or batteries as emergency power supplies. Smart Grids allows power from these individual emergency sources to be shared between buildings in the event of a regional power outage or shortage of power supply, in order to maintain the minimum level of daily life throughout the district.
For example, if part of the emergency power supply owned by a commercial facility or office building can be supplied to the elevators in residences or meeting halls in the event of a regional power outage, it will assure safety, relief, and convenience for the entire district. Securing backup energy can be expected to form communities oriented towards self-help, mutual help, and public help, and to lead to livelier communication in the entire district.
In Smart Cities, reduction of environmental loads in public transport is also an important element, along with power supply. Measures including rental cycles, car sharing, LRT (Light Rail Transit) as next-generation trams, and TOD (Transit Oriented Development), in which stations are centered in the development are implemented to develop more compact cities and improve their environments.

Although a smart grid draws attention for its energy-saving performance, the network between buildings with diverse power supply infrastructure may be a reliable backup under emergency conditions.

Since the Great East Japan Earthquake, the society strongly recognized that electricity resource is finite. Power sharing between buildings is important to efficiently use this finite resource and an aggregator coordinates the stakeholders.

Negawatt trading is deemed to become major by 2020. Power system design should be considered with power saving and creation measures (PV, CGS, batteries and heat storage) for Negawatt trading with aggregators.

Along with the growing market size of hydrogen, a new grid of heat, hydrogen and direct current would possibly be constructed. If hydrogen, generated with CO2-free, is used for FCVs and fuel cells and exhasut heat is used for district heating and cooling, cities would become low-carbon.

FIT (feed-in tariffs) is accelerating the installation of renewable energy equipment. Although some regions concern the unbalance of supply and demand, power sharing nationaly is still restricted. Local production and consumption of energy through Smart Energy Networks would make a considerable contribution to grid stabilization.

If power sharing networks that allow large emergency generators installed in large-sacle buildings to supply emergency power to nearby buildings are constructed, the power supply reliability for the whole district would be enhanced.

The idea of the “sharing economy” is to effectively share personal assets, to make cities more convenient. The lender gains income from idle assets, and the borrower can use assets without having to own them.

These ideas originated with "ID200", an activity where about our 200 engineers from the Building Services Design Division propose suggestions each year.