Increasing energy demand with limited resources is an obstacle in supplying demand for electrical energy sources at this time. The solution to this problem becomes essential due to the planning of excessive energy supply, as well as planning that does not meet the energy demand will cause new problems on the side of energy production. Therefore accurate energy consumption forecasting is very important. In this study, the projected use of energy in the processing industry sector in Bali uses LEAP software using a database from 2015 to 2018. The use of fuels in the processing industry in Bali according to modeling results will continue to increase until 2050. This increase due to an increase in population resulting in increased demand for processing industry products so that the production of processing industries has increased which directly increases fuel consumption. This increase in production is also due to increased purchasing power, this is shown from the increase in per capita GRDP of Bali province which has increased until 2050. GRDP of the processing industry according to modeling results has increased until 2050 this is in accordance with the energy needs of the processing industry , where an increase in the production of the processing industry will also result in an increase in the GRDP of the processing industry

Solar Rooftop PV is one solution in reducing CO2 emissions and the increasing consumption of electrical energy. Based on PP No.79 of 2014, Indonesia is committed to utilizing 23% of the total renewable energy of the total by 2025. In the General National Energy Plan (RUEN), in 2025 Indonesia targets the capacity of electrical energy from new and renewable energy of 45 GW of which solar power of 6.5 GW (14%). In this research, we will discuss the design of Solar Rooftop PV in the Udayana University Library building. Based on the helioscope simulation results, at a real angle of 20.6o and 20.3o solar modules that can be installed as many as 84 units with a power capacity of 28.1 kWp while at an optimum angle of 14.66o, as many as 66 solar modules can be installed with power capacity of 22.1 kWp. Based on the results of the HOMER simulation, the configuration between the real angle PV mini-grid and the grid is able to produce energy of 83,253 kWh/year with an emission reduction of 41.764%, while the configuration of the Solar Rooftop PV with the optimum installation angle with the grid is able to produce energy of 79.775 kWh/year with a reduction in emissions of 34.527%. From the results of the HOMER simulation, an economic analysis was carried out with an energy selling price of Rp. 900/kWh. The two Solar Rooftop PV designs are worth investing in where the Solar Rooftop PV design with a real installation angle of 20.6o and 20.3o is able to return the initial investment costs in the 17th year while the Solar Rooftop PV design with an optimum installation angle of 14.66o able to return the investment cost in the 20th year.

The wheelbarrow is a tool for transporting material in mining, plantation, and other areas that is pushed by one person with two rear handles and one wheel in the front. However, its use still requires and relies on a large amount of human power. The workers still have to expend energy to push the wheelbarrow which of course will be very heavy if the load is added in the wheelbarrow. Therefore, it is necessary to add an additional driving force to the wheelbarrow that can help the workers so that they can save their energy and also can make work more efficient. This wheelbarrow will use a DC motor as the driver and use Arduino uno with the PWM method as the control system. In addition, the tool will use a Lithium-ion battery so that it is more durable and can be easily recharged. The battery used has a voltage of 24V and a capacity of 9Ah. This semi-automatic wheelbarrow that uses a dc motor can help work faster up to about 32.5% more efficiently than without using a dc motor. In addition to being more efficient in use, wheelbarrows with dc motors also make it easier for users to use these tools compared to wheelbarrow without dc motors.

Utilization of renewable energy as a source of electrical energy is an environmentallyfriendly energy development, one of which is the use of solar energy by developing solar PV onthe roof of buildings as a medium for installing solar modules. In this study, a rooftop solar PVplan was carried out at the Nangka Utara gas station as a source of electrical energy whichaims to reduce the cost of PLN electricity bills. The rooftop solar PV system at the Nangka Utaragas station uses an On-grid solar PV system without batteries, using 36 units of 415 Wpmonocrystalline solar modules and one 15kW inverter unit. Planning for rooftop solar PV of theNangka Utara gas station with a capacity of 14.9 kWp with the resulting energy production of20.43 MWh per year. The initial investment cost required is IDR. 101.179,000 with a paybackperiod of 5 years and 8 months.

The utilization of renewable energy can be a solution to meet the current increasing demand for electrical energy in rural areas, one of which is the use of water energy with the development of PLTMH. In this study, the planning of a microhydro power plant was carried out in the irrigation canal of Angantaka Abiansemal Badung Village as a source of electrical energy to meet the needs of electrical energy. The Angantaka Village irrigation channel has a head 2,1 meters, a width of 1,95 meters, an average depth of 0,88 meters and a water discharge of 0,3045 m3/s. The PLTMH planning system uses a breastshot wheel type water wheel with an efficiency of 75% and TEK STC-5 kW 3 phase AC synchronous generator and a 6 kW ELC control panel. Planning for PLTMH on the irrigation canal of Angantaka Abiansemal Badung Village with a capacity of 3,76 kW / 4,70 kVA. The initial investment cost required is IDR. 72.055.375 with operational and maintenance cost of IDR. 720.553 in one year.